Managing herpes zoster, “the fire of God”
Herpes zoster is a viral infection that appears as red blisters on the skin and manifests with associated nerve pain. The outbreak usually follows an area of skin that correlates with a particular nerve root (a dermatome). It is caused by the varicella-zoster virus, the same virus that causes chickenpox.
Primary infection presents as varicella (or chickenpox), a contagious and usually benign illness that occurs in epidemics among susceptible children. After recovery from primary infection, varicella-zoster virus is not eliminated from the body but rather, the virus lies dormant in the sensory nervous system. Subsequent reactivation of latent varicella-zoster virus in nerve cells leads to a skin rash or blisters termed herpes zoster (or shingles).
Declining immunity, which can occur naturally as a result of aging or is induced by immuno-suppressive illness or medical treatments, increase the risk of shingles. Herpes zoster can occur in individuals that are emotionally stressed, deficient in vitamins and minerals, immuno-compromised, are severely ill, or are exposed to extreme temperatures. Individuals who had chickenpox can get herpes zoster if the virus becomes active, otherwise the virus remains dormant (inactive). Not all who had chickenpox will get shingles.
Herpes zoster affects men and women equally. But it is most common in children, people over the age of 60, and immuno-compromised individuals, and people receiving immune suppressive drugs like corticosteroids. Organ-transplant recipients are at a higher risk of getting herpes zoster.
Herpes zoster occurs with higher frequency among persons who are sero-positive for HIV than among those who are sero-negative. People with AIDS may have recurrent or prolonged zoster or multiple dermatome involvement, and zoster in a person at risk of HIV may be an indicator of unrecognised HIV infection.
The initial symptom of shingles is burning pain in the affected area. About 2-3 days after onset of pain, a rash will develop. The pain and rash usually follow one or more dermatomes. Usually only one side of the body is affected. The trunk and back are the most common areas affected, though anywhere on the body can be affected because of nerve involvement.
The rash consists of small reddish blisters that break open and ooze a honey colored liquid then crust over. The painful blisters will continue to form for 3-5 days, then resolve on their own.
The pain that is associated with shingles can take much longer to resolve. It is usually described as burning and can become very intense. In some cases, individuals may have pain for months to years after the skin eruption has resolved. This diagnosis is called post-herpetic neuralgia. Very few patients will have a reoccurrence of the shingles. This is a distinguishing fact from herpes simplex virus. Complications can occur if the virus infects nerve roots that innervate the eye, internal organs, or the inner ear.
With herpes zoster, one has to be careful not to infect the eyes. Do not touch the blisters with your hand and then to the eyes. The virus has the capacity to spread through the nerves and infect the eyes. Herpes zoster is one of the main causes of blindness.
Treatment of herpes zoster is focused on the treatment of pain-related symptoms. The rash disappears on its own, usually over 5-7 days and requires no formal treatment. Conventional treatments for the pain and possible post-herpetic neuralgia include pain-killing (analgesic) medications, and in severe cases, anti-depressants.
Pain, particularly persistent pain, is thought to be largely the result of virus-induced damage to the affected sensory nerve cells. The rationale behind the use of antiviral agents is simple: by stopping virus production as quickly as possible, nerve damage is minimised. Antiviral therapy is appropriate for all patients presenting with shingles within 72 hours of rash onset.
Three drugs – acyclovir (Zovirax), valacyclovir (Valtrex), and famciclovir (Famvir) – are approved in the United States for the treatment of herpes zoster.
Acyclovir (800 mg five times daily) shortens the duration of viral shedding, halts the formation of new lesions more quickly, accelerates the rate of healing, and reduces the severity of acute pain.
Valacyclovir (1000 mg every eight hours), a pro-drug of acyclovir, produces serum acyclovir levels that are three to five times as high as those achieved with oral acyclovir therapy.
Because of their superior pharmacokinetic profiles and simpler dosing regimens, valacyclovir and famciclovir (500 mg every eight hours) are preferred to acyclovir for the treatment of herpes zoster. Sorivudine is also an effective drug for the treatment of herpes zoster in HIV-infected patients and results in accelerated healing when compared with acyclovir therapy. None of these drugs are currently approved for use in pregnant women.
Individuals that are immuno-compromised will usually be given acyclovir, or a similar antiviral to prevent complications and reoccurrence.
Management of herpes zoster can include: vitamin B12 or vitamin B complex (is good for nerves), vitamin C (to boost immune system), Capsaicin cream (put on the 0.025 to 0.075% capsaicin extract 2 to 4 times daily to shingles area to help relieve pain), olive leaf extract (take 500 mg, 4 times daily to boost the immune system and help keep the virus under control), Echinacea (take 4 ml or 500 mg, 4 times daily to boost the immune system and help keep the virus under control), and vitamin E-complex (take 1200 to 1600 IU daily to prevent neuralgia).
The rash and pain usually subside within 3-5 weeks. The most common chronic complication of herpes zoster is post-herpetic neuralgia. Pain that persists for longer than 1-3 months after resolution of the rash is generally accepted as the sign of post-herpetic neuralgia. Pain management is difficult as conventional analgesics may be ineffective. Alternative agents are often used, including tricyclic anti-depressants (particularly amitriptyline), anti-convulsants (e.g. gabapentin, or topical capscaicin).
Sometimes serious effects including partial facial paralysis (usually temporary), ear damage, or encephalitis may occur. Shingles on the upper half of the face may result in eye damage and require urgent specialist ophthalmological assessment.
Post-herpetic neuralgia may cause persistent pain that lasts for years. Zostavax is a vaccine developed by Merck & Co which has proven successful in preventing half the cases of herpes zoster in a study of 38,000 people who received the vaccine. The vaccine also reduced by two-thirds the number of cases of post-herpetic neuralgia. The varicella-zoster virus Oka strain vaccine is currently recommended by the Advisory Committee on Immunization Practices for universal childhood vaccination.
Glycyrrhizin, a component of Glycyrrhiza glabra or licorice, is a root that produces anti-inflammatory substances. Licorice root has been shown to inhibit varicella zoster virus in the lab. This anti-viral activity is believed to be effective in the body as well, though no studies have been performed. One study found that the topical application of glycyrrhizin decreased the intensity of pain in patients with herpes zoster. It was found to be as effective as acyclovir.
Capsaicin cream is a well-documented treatment for the pain associated with shingles. It is effective for long-term use in the case of post-herpetic neuralgia as well. Vitamin E has also been used as a topical application for post-herpetic neuralgia. There is conflicting evidence in the literature, and its effectiveness in shingles treatment remains unclear.
l KC is a lecturer at the University of Namibia. Email comments to: firstname.lastname@example.org